Smallest possible three man craft to 65km Laythe orbit.

[Motokid600]

Im building a mission out to Jool to perform various tasks, but the main one is to land three kerbals on Laythe, drive around the island and return them home. That last one I find is what makes this very hard lol. Im doing this Apollo style with a CM orbiter and I need this LM to be able to return to the CM where it will then be ditched.. sadly. ( Once that gets built ) So im just building and testing ideas for a good ascent craft.

I dont do orbital construction. So to get this behemoth into orbit once its done I will need a very large rocket. My goal is to make each stage as small and compact as possible to ease this process. Heres what ive been playing with.

Im using various mods. KW, Nova ( the radial SRB's and tiny decouplers ) Home ( small radial ascent engines ) B9 for their flat mono tanks.

The parachutes decouple off the top after landing. On take off the legs detach and the twelve SRB's fire getting the craft up to about 3,500m before they decouple and the radial engines fire. At this point the craft possesses 2,500 Dv and gets up to about 30,000m. Im testing on this on Kerbin so I figure if it can be done on Kerbin it can be done on Laythe.

What im looking for is input on the ascent stage. Is there a way I can do this more efficiently and retain a compact design? And one that's less crashy maybe.. for some reason my game likes to crash on the surface of Kerbin and I suspect the SRB's to be the culprit. So they may have to go. That may mean back to the drawling board which brings me here. I need to get to a circular 65km orbit and have enough fuel to put around for a rendezvous. Heres another pic of the descent stage. Subject to change, but it works for now.

Edited August 3, 2013 by Motokid600

[dlmarti]

I don't know enough about the parts you are using, to understand their pros/cons.

If you checked it out on Engineer Redux, then it should work.

[Geschosskopf]

Well, if you're going for smallest possible, 3 command chairs on an I-beam is pretty hard to beat.

[Motokid600]

Well how would you do it? I believe the craft will work. You need 2,800 Dv according to the map to get to a 65km orbit. Id like to think the SRB's will make up for the 300 im short on. But regardless if this design works or not is there a way to do it...better? A more efficient design with less parts and that's even smaller if possible.

[Sauron]

Fewer parts? There is no way you need all those radial engines (though it is a very pretty ship set up this way). Radials, are less efficient than their stack-mounted counterparts. You could cluster an LV-T45 (or better yet, a 909) and some aerospikes to get an almost-SSTO on Kerbin and a true SSTO on Laythe.

Edit: after copying your clever aesthetics, I got 2917 m/s (and a very high TWR--if you sacrifice aesthetics you could get more, but powering through your ascent reduces gravity losses) with 6 T-400s, and 1 x200 with 6 aerospikes and 1 909 for orbital manuvers. Photobucket is being stupid at the moment, but that's the gist of it

It's probably a touch heavier than your design in the interest of avoiding excessive part clipping, but you could shrink the concept easily enough.

Edited August 3, 2013 by Sauron